The present invention relates to a cooler arrangement for a vehicle which is powered by a supercharged combustion engine.
The development of the performance of combustion engines and the requirement for ever lower emissions in their exhaust gases have resulted in ever increasing cooling requirements in vehicles. The air which is led to a combustion engine is compressed to high pressure before it is led to the engine. Compressing the air causes it to acquire a raised temperature which is related to the degree of compression. To reduce the volume of the compressed air, it is cooled in one or more charge air coolers before it is led to the engine. The technique called EGR (exhaust gas recirculation) is a known way of leading back part of the exhaust gases of a combustion engine. Adding exhaust gases to the air causes a lower combustion temperature resulting inter alia in a reduced content of nitrogen oxides NOx in the exhaust gases. The exhaust gases from a combustion engine may be at a high temperature. To reduce the volume of the recirculating exhaust gases, they are cooled in one or more EGR coolers before being mixed with the air and led to the engine. Effective cooling of the compressed air and the recirculating exhaust gases makes it possible for a large amount of air and exhaust gases to be led to the engine. The performance of a combustion engine increases with the amount of air and recirculating exhaust gases supplied.
US 2009/0211253 refers to an energy recovery arrangement whereby a circulating medium absorbs thermal energy from a plurality of heat exchangers in the form of, inter alia, a charge air cooler and an EGR cooler. The medium is warmed by the thermal energy absorbed to a temperature at which it vaporises. The vaporised medium has not only a raised temperature but also a raised pressure. The medium is then led through a turbine. Part of the thermal energy absorbed is converted in the turbine to mechanical energy. The medium is led thereafter to a condenser in which it is cooled by a cooling air flow to a temperature at which it condenses. The resulting liquid medium is circulated from the condenser back to said coolers in order to again absorb thermal energy so that it becomes vaporised.